from pygem.cffd import CFFD
import numpy as np
[docs]
class VFFD(CFFD):
'''
Class that handles the Volumetric Free Form Deformation on the mesh points.
:param list n_control_points: number of control points in the x, y, and z
direction. Default is [2, 2, 2].
:param string mode: it can be ``affine`` or ``triaffine``. The first option is for the F that are affine in all the coordinates of the points.
The second one is for functions that are F in the coordinates of the points. The first option implies the second, but is optimal for that class of functions.
:cvar numpy.ndarray box_length: dimension of the FFD bounding box, in the
x, y and z direction (local coordinate system).
:cvar numpy.ndarray box_origin: the x, y and z coordinates of the origin of
the FFD bounding box.
:cvar numpy.ndarray n_control_points: the number of control points in the
x, y, and z direction.
:cvar numpy.ndarray array_mu_x: collects the displacements (weights) along
x, normalized with the box length x.
:cvar numpy.ndarray array_mu_y: collects the displacements (weights) along
y, normalized with the box length y.
:cvar numpy.ndarray array_mu_z: collects the displacements (weights) along
z, normalized with the box length z.
:cvar callable fun: it defines the F of the constraint F(x)=c. Default is the constant 1 function.
:cvar numpy.ndarray fixval: it defines the c of the constraint F(x)=c. Default is 1.
:cvar numpy.ndarray ffd_mask: a boolean tensor that tells to the class
which control points can be moved, and in what direction, to enforce the constraint.
The tensor has shape (n_x,n_y,n_z,3), where the last dimension indicates movement
on x,y,z respectively. Default is all true.
:cvar numpy.ndarray fun_mask: a boolean tensor that tells to the class
on which axis which constraint depends on. The tensor has shape (n_cons,3), where the last dimension indicates dependency on
on x,y,z respectively. Default is all true. It used only in the triaffine mode.
:Example:
>>> from pygem import VFFD
>>> import numpy as np
>>> import meshio
>>> mesh = meshio.read('tests/test_datasets/test_sphere_cffd.stl')
>>> original_mesh_points = mesh.points
>>> triangles = mesh.cells_dict["triangle"]
>>> b = np.random.rand(1)
>>> vffd = VFFD(triangles, b, [2, 2, 2])
>>> vffd.read_parameters('tests/test_datasets/parameters_test_cffd.prm')
>>> vffd.adjust_control_points(original_mesh_points)
>>> new_mesh_points = vffd(original_mesh_points)
>>> assert np.isclose(np.linalg.norm(vffd.fun(new_mesh_points) - b), np.array([0.]), atol=1e-07)
'''
def __init__(self, triangles, fixval, n_control_points=None, ffd_mask=None):
super().__init__(fixval, None, n_control_points, ffd_mask, None)
self.triangles = triangles
def volume_inn(x):
return _volume(x, self.triangles)
self.fun = volume_inn
self.fixval = fixval
self.fun_mask = np.array([[True, True, True]])
def _volume(x, triangles):
x = x.reshape(-1, 3)
mesh = x[triangles]
return np.array([np.sum(np.linalg.det(mesh))])